<!DOCTYPE html>
<html>
<head>
<style>
* {
    margin: 0;
    padding: 0;
}
</style>
</head>
<body>
<div style="width: 500px; text-align: center;">
    <span style="display: inline-block; width: 150px; height: 50px; background: blue;"></span><span style="display: inline-block; width: 350px; height: 50px; background: green;"></span>
</div>
</body>
</html>

